288 AXILLARY ARTERY. 



Dr. Harrison, " are remarkable for the number of their inosculations, 

 and for the distant parts of the arterial system which they serve to 

 connect. They anastomose with each other, and their inosculations, 

 with the thoracic aorta, encircle the thorax. On the parietes of this 

 cavity their branches connect the axillary and subclavian arteries ; 

 on the diaphragm they form a link in the chain of inosculations be- 

 tween the subclavian artery and abdominal aorta, and in the parietes 

 of the abdomen they form an anastomosis most remarkable for the 

 distance between those vessels "which it serves to connect ; namely, 

 the arteries of the superior and inferior extremities." 



Varieties of the Subclavian Arteries. Varieties in these arteries 

 are rare ; that whjch most frequently occurs is the origin of the right 

 subclavian, from the left extremity of the arch of the aorta, below 

 the left subclayian artery. The vessel, in this case, curves behind 

 the oesophagus and right carotid artery, and sometimes between the 

 O3sophagus and trachea, to the upper border of the first rib, on the 

 right side of the chest, where it assumes its ordinary course. In a 

 case* of subclavian aneurism on the right side, above the clavicle, 

 which happened during the present summer, Mr. Liston proceeded 

 to perform the operation of tying the carotid and subclavian arteries 

 at their point of division from the innominata. Upon reaching the 

 point where the bifurcation should have existed, he found that there 

 was no subclavian artery. With that admirable self-possession 

 which distinguishes this eminent surgeon in all cases of emergency, 

 he continued his dissection more deeply, towards the vertebral 

 column, and succeeded in securing the artery. It was ascertained 

 after death, that the arteria innominata was extremely short, and 

 that the subclavian was given off within the chest from the posterior 

 aspect of its trunk, and pursued a deep course to the upper mar- 

 gin of the first rib. In a preparation which was shown to me in 

 Heidelberg some years since by Professor Tiedemann, the right 

 subclavian artery arose from the thoracic aorta, as low down as 

 the fourth dorsal vertebra, and ascended from that point to the 

 border of the first rib. Varieties in the branches of the subclavian 

 are not unfrequent ; the most interesting is the origin of the left 

 vertebral, from the arch of the aorta, of which I possess several 

 preparations. 



AXILLARY ARTERY. 



The axillary artery forms a gentle curve through the middle of the 

 axillary space from the lower border of the first rib to the lower 

 border of the latissimus dorsi, where it becomes the brachial. 



Relations. After emerging from beneath the margin of the costo- 

 coracoid membrane, it is in relation with the axillary vein, which 

 lies at first to the inner side and then in front of the artery. Near 

 the middle of the axilla it is embraced by the two heads of the 

 median nerve, and is covered in by the pectoral muscles. Upon the 



* This case is recorded in the Lancet, Vol. 1. 1839-40, pp. 37 and 419. 



